This invention relates, in part, to newly identified methods of using quinolone antibiotics, particularly a gemifloxacin compound against anaerobic bacteria, especially unusual anaerobic bacteria.
Quinolones have been shown to be effective to varying degrees against a range of certain anaerobic pathogens. However, as diseases caused by these pathogens are on the rise, there exists a need for antimicrobial compounds that are more potent than the present group of quinolones.
Gemifloxacin mesylate (SB-265805) is a novel fluoroquinolone useful as a potent antibacterial agent. Gemifloxacin compounds are described in detail in patent application PCT/KR98/00051 published as WO 98/42705. Patent application EP 688772 discloses novel quinoline(naphthyridine)carboxylic acid derivatives, including anhydrous (R,S)-7-(3-aminomethyl-4-methoxyiminopyrrolidin- 1 -yl)-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid of formula I. 
PCT/KR98/00051 discloses (R,S)-7-(3-aminomethyl4-syn-methoxyimino-pyrrolidin-1-yl)-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid methanesulfonate and hydrates thereof including the sesquihydrate.
While in vitro testing of new antimicrobial compounds is often extensive, these studies tend to focus on a limited range of typical anaerobic bacterial pathogens (Cormicon, et al., Antimicrob. Agents Chemother., 41:204-211, 1997; Hohl, et al., Clin. Microbiol. Infect., 4:280-284, 1998; Marco, et al., J. Antimicrob. Chemother., 40:605-607, 1997). Moreover, it has been reported that (Goldstein, et al., Antimicrob. Agents Chemother., Submitted) the activity of gemifloxacin against typical anaerobic bacteria; it showed activity against Bacteroides fragilis and certain Prevotella and Porphyromonas strains, but only limited activity against B. thetaiotaomicron, B. distasonis and B. ovatus. Data is lacking about the activities of new quinolone compounds against many of the less frequently encountered anaerobic pathogens, such as Actinomyces spp., Anaerobiospirrilum spp., Porphyromonas spp., and Bilophila wadsworthia. 
Provided herein is an invention based, in part, on a significant discovery made using a gemifloxacin compound against various unusual, though medically impotant, anaerobic bacteria, demonstrating the activity of the gemifloxacin compound used was superior to a number of quinolones as described in more detail herein. Gemifloxacin compounds are valuable compounds for the treatment of bacterial caused by a range of anaerobic pathogens, including those resistant to usual oral therapy, thereby filling an unmet medical need.
An object of the invention is a method for modulating metabolism of anaerobic pathogenic bacteria comprising the step of contacting anaerobic pathogenic bacteria with an antibacterially effective amount of a composition comprising a quinolone, particularly a gemifloxacin compound, or an antibacterially effective derivative thereof.
A further object of the invention is a method wherein said anaerobic pathogenic bacteria is selected from the group consisting of: a member of the genus Peptostreptococci, a Peptostreptococci asaccharolyticus, a Peptostreptococci magnus, a Peptostreptococci micros, a Peptostreptococci prevotii, a Porphyromonas asaccharolytica, a Porphyromonas canoris, a Porphyromonas gingivalis, a Porphyromonas macaccae, a member of the genus Actinomyces, an Actinomyces israelii, an Actinomyces odontolyticus, a member of the genus Clostridium, a Clostridium innocuum, a Clostridium clostridioforme, a Clostridium difficile, a member of the genus Anaerobiospirillum, a Bacteroides tectum, a Bacteroides ureolyticus, a Bacteroides gracilis (Campylobacter gracilis), a Prevotella intermedia, a Prevotella heparinolytica, a Prevotella oris-buccae, a Prevotella bivia, a Prevotella melaninogenica, a member of the genus Fusobacterium, a Fusobacterium naviforme, a Fusobacterium necrophorum, a Fusobacterium varium, a Fusobacterium ulcerans, a Fusobacterium russii, a member of the genus Bilophila, a Bilophila wadsworthia. 
Also provided by the invention is a method of treating or preventing a bacterial infection by anaerobic pathogenic bacteria comprising the step of administering an antibacterially effective amount of a composition comprising a quinolone, particularly a gemifloxacin compound to a mammal suspected of having or being at risk of having an infection with anaerobic pathogenic bacteria.
A preferred method is provided wherein said modulating metabolism is inhibiting growth of said bacteria or killing said bacteria.
A further preferred method is provided wherein said contacting said bacteria comprises the further step of introducing said composition into a mammal, particularly a human.
Further preferred methods are provided by the invention wherein said bacteria is selected from the group consisting of: a member of the genus Peptostreptococci, a Peptostreptococci asaccharolyticus, a Peptostreptococci magnus, a Peptostreptococci micros, a Peptostreptococci prevotii, a member of the genus Porphyromonas, a Porphyromonas asaccharolytica, a Porphyromonas canoris, a Porphyromonas gingivalis, a Porphyromonas macaccae, a member of the genus Actinomyces, an Actinomyces israelii, an Actinomyces odontolyticus, a member of the genus Clostridium, a Clostridium innocuum, a Clostridium clostridioforme, a Clostridium difficile, a member of the genus Anaerobiospirillum, a member of the genus Bacteroides, a Bacteroides tectum, a Bacteroides ureolyticus, a Bacteroides gracilis (Campylobacter gracilis), a member of the genus Prevotella, a Prevotella intermedia, a Prevotella heparinolytica, a Prevotelia oris-buccae, a Prevotella bivia, a Prevotella melaninogenica, a member of the genus Fusobacterium, a Fusobacterium naviforme, a Fusobacterium necrophorum, a Fusobacterium varium, a Fusobacterium ulcerans, a Fusobacterium russii, a member of the genus Bilophila, a Bilophila wadsworthia. 
Various changes and modifications within the spirit and scope of the disclosed invention will become readily apparent to those skilled in the art from reading the following descriptions and from reading the other parts of the present disclosure.
The present invention provides, among other things, methods for using a composition comprising a quinolone, particularly a gemifloxacin compound against anaerobic bacteria.
As used herein xe2x80x9cgemifloxacin compound(s)xe2x80x9d means a compound having antibacterial activity described in patent application PCT/KR98/00051 published as WO 98/42705, or patent application EP 688772.
This invention was based, in part, on analyses evaluating the comparative activity of gemifloxacin against various anaerobic pathogens. Since anaerobic susceptibility testing is not routinely performed in most clinical laboratories, if it is performed at all, the clinician must rely on published studies to help guide both empirical therapy as well as specific therapy in situations that involve less commonly isolated or identified anaerobes or mixed infections at other sites. Most in vitro studies of gemifloxacin against anaerobic bacteria focus their attention on common intra-abdominal pathogens such as Bacteroides fragilis and Clostridium perfringens or lump the anaerobes into large groups without speciation (Cormicon, et al., Antimicrob. Agents Chemother., 41:204-211, 1997; Marco, et al., J. Antimicrob. Chemother., 40:605-607, 1997). Consequently there is unmet medical need for data regarding certain species often recovered from respiratory and gynecological infections as well as less frequently identified components of mixed abdominal infections, as well as methods used for ther treatment of such pathogens.
The present invention was based, in part, on analyses showing that gemifloxacin compared favorably with trovafloxacin against the Gram-positive anaerobes tested as well as the other unusual isolates studied [see, for example, Table 1]. Cormicon and Jones (Cormicon, et al., Antimicrob. Agents Chemother., 41:204-211, 1997) studied 10 strains of peptostreptococci and found an MIC90 of 2 ug/ml for gemifloxacin which is in contrast to our study which included 45 strains of peptostreptococci from 4 species, all of which were susceptible to ⇄0.25 ug/ml of gemifloxacin. The reason for this discrepancy can not be accounted for by methodological variations since both studies used brucella agar and an agar dilution method. Marco, et al. (Marco et al. J. Antimicrob. Chemother., 40:605-607, 1997) studied 18 strains of peptostreptococci and also found an MIC90 of 2 ug/ml [range, ⇄0.25-8 ug/ml] for gemifloxacin.
Differences in the susceptibility of different Clostridium species to gemifloxacin were apparent in assays described herein, with C. clostridioforme and C. innocuum being relatively susceptible while C. difficile was often resistant to gemifloxacin. In the current study, the ten C. ramosum isolates studied had an MIC90 of 1 ug/ml while a prior study (Goldstein, et al., Antimicrob. Agents Chemother, Submitted) the MIC90 for the 14 isolates studied was 8 ug/ml. With the exception of two strains, all isolates in these two studies were different and most came from blood cultures. The apparent disparity comes from the higher MICs of 3/14 strains in the prior study and highlights the problem of testing small numbers of isolates of a single species, which has been solved by the analyses underpinning certain embodiments of the current invention. Further, Cormicon and Jones (Cormicon, et al., Antimicrob. Agents Chemother., 41:204-211, 1997) studied ten clostridial isolates and found a maximum MIC of 2 ug/ml to gemifloxacin. Marco, et al. (Marco, et al., J. Antimicrob. Chemother. 40:605-607, 1997) reported all 19 unspecieted clostridial isolates they studied to be susceptible to ⇄2 ug/ml.
The data presented herein shows that there is marked variation in susceptibility patterns of different anaerobic genera and species to trovafloxacin and gemifloxacin and that important clinical anaerobic isolates should have individual strain susceptibilities determined. It is difficult to predict susceptibility based on a grouping of several species in a less commonly encountered or identified genus, and this problem has been solved in the methods of the invention.
Gemifloxacin exhibited good activity against Gram-positive anaerobes, especially the four Peptostreptococcus species tested, as well as the Porphyromonas species tested.
As provided herein, activities of gemifloxacin and comparator antimicrobial agents were determined by an agar dilution method against 419 clinical strains of less commonly identified, though medically important, species of anaerobes. Gemifloxacin was generally more active than trovafloxacin against Gram-positive strains by one to two dilutions. Peptostreptococci [P. asaccharolyticus, P. magnus, P. micros, and P. prevotii] and Porphyromonas spp. [P. asaccharolytica, P. canoris, P. gingivalis, P. macaccae] were all susceptible to ⇄0.25 ug/ml of gemifloxacin. Actinomyces israelii, Actinomyces odontolyticus, Clostridium innocuum, Clostridium clostridioforme, Anaerobiospirillum spp., Bacteroides tectum, B. ureolyticus, B. gracilis [now Campylobacter gracilis], Prevotella intermedia, Prevotella heparinolytica, Prevotella oris-buccae group had MIC90s of ⇄2 xcexcg/ml. Fusobacterium naviforme and F. necrophorum were also susceptible to ⇄2 xcexcg/ml, while F. varium strains exhibited a bimodal pattern; the other Fusobacterium species, such as F. ulcerans, F. russii, as well as Veillonella spp., Prevotella melaninogenica group, P. bivia, Clostridium difficile, and Bilophila wadsworthia were relatively resistant to gemifloxacin [MIC90s ↓4 ug/ml].(See Table 1).
The invention provides a method for modulating metabolism of anaerobic pathogenic bacteria. Skilled artisans can readily choose anaerobic pathogenic bacteria or patients infected with or suspected to be infected with these organisms to practice the methods of the invention. Alternatively, the bacteria useful in the methods of the invention may be those described herein.
The contacting step in any of the methods of the invention may be performed in many ways that will be readily apparent to the skilled artisan. However, it is preferred that the contacting step is a provision of a composition comprising a gemifloxacin compound to a human patient in need of such composition or directly to bacteria in culture medium or buffer.
For example, when contacting a human patient or contacting said bacteria in a human patient or in vitro, the compositions comprising a quinolone, particularly a gemifloxacin compound, preferably pharmaceutical compositions may be administered in any effective, convenient manner including, for instance, administration by topical, oral, anal, vaginal, intravenous, intraperitoneal, intramuscular, subcutaneous, intranasal or intradermal routes among others.
It is also preferred that these compositions be employed in combination with a non-sterile or sterile carrier or carriers for use with cells, tissues or organisms, such as a pharmaceutical carrier suitable for administration to a subject. Such compositions comprise, for instance, a media additive or a therapeutically effective amount of a compound of the invention, a quinolone, preferably a gemifloxacin compound, and a pharmaceutically acceptable carrier or excipient. Such carriers may include, but are not limited to, saline, buffered saline, dextrose, water, glycerol, ethanol and combinations thereof. The formulation should suit the mode of administration.
Quinolone compounds, particularly gemifloxacin compounds and compositions of the methods of the invention may be employed alone or in conjunction with other compounds, such as bacterial efflux pump inhibtor compounds or antibiotic compounds, particularly non-quinolone compounds, e.g., beta-lactam antibiotic compounds.
In therapy or as a prophylactic, the active agent of a method of the invention is preferably administered to an individual as an injectable composition, for example as a sterile aqueous dispersion, preferably an isotonic one.
Alternatively, the gemifloxacin compounds or compositions in the methods of the invention may be formulated for topical application for example in the form of ointments, creams, lotions, eye ointments, eye drops, ear drops, mouthwash, impregnated dressings and sutures and aerosols, and may contain appropriate conventional additives, including, for example, preservatives, solvents to assist drug penetration, and emollients in ointments and creams. Such topical formulations may also contain compatible conventional carriers, for example cream or ointment bases, and ethanol or oleyl alcohol for lotions. Such carriers may constitute from about 1% to about 98% by weight of the formulation; more usually they will constitute up to about 80% by weight of the formulation.
For administration to mammals, and particularly humans, it is expected that the antibacterially effective amount is a daily dosage level of the active agent from 0.001 mg/kg to 10 mg/kg, typically around 0.1 mg/kg to 1 mg/kg, preferably about 1 mg/kg. A physician, in any event, will determine an actual dosage that is most suitable for an individual and will vary with the age, weight and response of the particular individual. The above dosages are exemplary of the average case. There can, of course, be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention. It is preferred that the dosage is selected to modulate metabolism of the bacteria in such a way as to inhibit or stop growth of said bacteria or by killing said bacteria. The skilled artisan may identify this amount as provided herein as well as using other methods known in the art, e.g. by the application MIC tests.
A further embodiment of the invention provides for the contacting step of the methods to further comprise contacting an in-dwelling device in a patient. In-dwelling devices include, but are not limited to, surgical implants, prosthetic devices and catheters, i.e., devices that are introduced to the body of an individual and remain in position for an extended time. Such devices include, for example, artificial joints, heart valves, pacemakers, vascular grafts, vascular catheters, cerebrospinal fluid shunts, urinary catheters, and continuous ambulatory peritoneal dialysis (CAPD) catheters.
A quinolone, particularly a gemifloxacin compound or composition of the invention may be administered by injection to achieve a systemic effect against relevant bacteria, preferably a anaerobic pathogenic bacteria, shortly before insertion of an in-dwelling device. Treatment may be continued after surgery during the in-body time of the device. In addition, the composition could also be used to broaden perioperative cover for any surgical technique to prevent bacterial wound infections caused by or related to anaerobic pathogenic bacteria.
In addition to the therapy described above, a gemifloxacin compound or composition used in the methods of this invention may be used generally as a wound treatment agent to prevent adhesion of bacteria to matrix proteins, particularly anaerobic pathogenic bacteria, exposed in wound tissue and for prophylactic use in dental treatment as an alternative to, or in conjunction with, antibiotic prophylaxis.
Alternatively, a quinolone, particularly a gemifloxacin compound or composition of the invention may be used to bathe an indwelling device immediately before insertion. The active agent will preferably be present at a concentration of 1 xcexcg/ml to 10 mg/ml for bathing of wounds or indwelling devices.
Also provided by the invention is a method of treating or preventing a bacterial infection by anaerobic pathogenic bacteria comprising the step of administering an antibacterially effective amount of a composition comprising a quinolone, particularly a gemifloxacin compound to a mammal, preferably a human, suspected of having or being at risk of having an infection with anaerobic pathogenic bacteria.
While a preferred object of the invention provides a method wherein said anaerobic pathogenic bacteria is selected from the group consisting of: selected from the group consisting of: a member of the genus Peptostreptococci, a Peptostreptococci asaccharolyticus, a Peptostreptococci magnus, a Peptostreptococci micros, a Peptostreptococci prevotii, a member of the genus Porphyromonas, a Porphyromonas asaccharolytica, a Porphyromonas canoris, a Porphyromonas gingivalis, a Porphyromonas macaccae, a member of the genus Actinomyces, an Actinomyces israelii, an Actinomyces odontolyticus, a member of the genus Clostridium, a Clostridium innocuum, a Clostridium clostridioforme, a Clostridium difficile, a member of the genus Anaerobiospirillum, a member of the genus Bacteroides, a Bacteroides tectum, a Bacteroides ureolyticus, a Bacteroides gracilis (Campylobacter gracilis), a member of the genus Prevotella, a Prevotella intermedia, a Prevotella heparinolytica, a Prevotella oris-buccae, a Prevotella bivia, a Prevotella melaninogenica, a member of the genus Fusobacterium, a Fusobacterium naviforme, a Fusobacterium necrophorum, a Fusobacterium varium, a Fusobacterium ulcerans, a Fusobacterium russii, a member of the genus Bilophila, a Bilophila wadsworthia. 
Other anaerobic pathogenic bacteria may also be included in the methods. The skilled artisan may identify these organisms as provided herein as well as using other methods known in the art, e.g. MIC tests.
Preferred embodiments of the invention include, among other things, methods wherein said composition comprises gemifloxacin, or a pharmaceutically acceptable derivative thereof.